A footwear article forming process, and a device for the same are disclosed. The process includes: providing a forming mold set including an outer modular mold, an inner formation mold, and a footwear-forming space therebetween. The footwear-forming space comprises a footwear lower portion forming space and a footwear main portion forming space. Footwear article forming steps are as follows: injecting a pre-determined amount of a footwear main portion rubber material into a footwear main portion sprue channel, the footwear main portion rubber material being injected from a footwear main portion rubber injection opening into the footwear main portion forming space via a transfer injection channel; and placing a footwear lower portion rubber material into the footwear lower portion forming space.